Preparation of fluorosulfur compounds



'itti tires 3,048,629 Patented Aug. 7, 1962 3 048,629 PREPARATION 6 F FLllJQRQSULFUR COMPOUNDS Kenneth Vincent Martin, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington,

tained through carbonization of the raw material followed by an activation step which involves the controlled oxidation of the carbonized material. The preparation of active carbon is well-known in industry and a number of active Del, a corporation of Deiaware o carbons are commercially available. No Drawing. Filed Apr 29, 1959, Sen 809,598 A large variety of fluorooletins may be employed in the 5 Clainm (CL 269M544) process of the present invention to prepare thiocarbonyl compounds. Depending on the number of carbon atoms The process of the present invention relates to the in the fluoroolefin and the location of the unsaturated preparation of sulfur-containing, fluorinated compounds, bond, the products are either thioacetyl fluorides or thioand, more particularly, to the preparation of fluorinated ketones. In terminally unsaturated fluoroolefins, the thiocarbonyl compounds from fluorinated olefins. ketones are formed in preference to the acetyl fluorides. Fluorothioacetyl halides and fluorothioketones are a The fluoroolefins employed may be branched, cyclic, or novel class of chemical compounds which show outstandinternally unsaturated. As indicated by the general ing technical promise as monomers for the preparation formula hereina-bove, it is not essential that all of the of thermally stable and corrosion-resistant elasto-mers. substituents on the double bond he fluorine or fluoro- Low molecular weight liquid polymers of these comcarbon radicals. Representative examples of the fluoropounds have properties which make them suitable for use olefins are tetrafluoroethylene, hexafluoropropylene, peras dielectric media, hydraulic fluids and inert solvents. fluorobutene-l, perfluorobutene-2-, perfluoroisobutylene,

It is, therefore, the principal object of the present in- 0 perfiuoropentene-l, perfluoropentene-Z, omega-hydropervention to provide a method for the preparation of fluorofluoropentene-l, perfluorooctene-l, perfluorododecene-l, thiocarbonyl compounds. omega hydroperfluoroheptene 1, perfluorocyclobutene,

The object of the present invention is accomplished by perfluorocyclohexene, trifluoroethylene, chlorotrifluoroa process which comprises contacting a mixture of a ethylene and the like. The preferred starting materials fluoroolefin having the general formula employed in the process of the present invention are those R2 having the general formula CF =CFC ,F ,,X, where n A is from 0 to 10 and X is selected from the class consisting RTC: of fluorine and hydrogen.

The ratio of the sulfur to the fluoroolefin is not critical; wherein R and R are the same or different radicals 0 f f it is Preferred to P Y at least equal molar selected from the class consisting of fluorine, perfluoroquantifies Ofsulfur and the fiuoTPolefincarbon radicals and divalent fluorocarbon radicals formed The Process of l Present Invention 15 further from the combination of R and R and R is a radical ated by the followmg examplesselected from the class consisting of hydrogen, halogen EXAMPLES I TO VI and perfluorocarbon radicals, and vaporized sulfur at a Th h d bl demonstrates h preparation f temperature of tO -r but p y at thiocarbonyl compounds in accordance with the present a temperature 05 to With activated invention and shows the conditions and results employed carbon, and recovering a fluorothiocarbonyl compound. i each example vaporized lf b i by heating In accordance the present invention, the fluorothio- Sulfur in a tainless steel vessel and assing nitrogen Carbonyl Compounds are Obtained y Passing a miXtUIe 40 through the molten sulfur, is admixed with the fluoroole- 0f vapofiz'id Sulfur and the fiuflmolefin through an fin indicated, and passed into a 1 in. nickel tube placed vated carbon bed maintained at the temperatures indii an upright position in a tube furnace, The fl f f The P 0C6S may be Can'ied 011i With an gas sulfur was regulated by the temperature of the sulfur pot Camel, 311611 35 nltfogfin y of the rare gases- The and the flow in the nitrogen. The tube contained a 7 contact time of the gas mixture with the carbon should in. packed bed of activated carbon, Cheney CH-Z, be long enough to alloW the gas to Come to the term commercially available from the Barnaby Cheney Corp., p rat lre 0f t a t Ca Th6 -F- heated by the tube furnace to the temperature indicated. bonyl compounds obtained are caught in a cold trap and The effluent gas was passed into a cold trap maintained at are then purified by distillation. F 78 C. which condensed the thiocarbonyl products Any type of active carbon can be employed as the formed. The thiocarbonyl products were isolated and catalyst in the present invention. In general, however, purified by distillation from the cold trap.

Table I Flow Temp. of Flow Carbon Example Fluoroolefin Rate, Sulfur Rate of Bed Reaction Product nil/mm. Vessel, Nitrogen Temp., Time C. ml./min. C.

tetratluoro- 150 422 150 422 120 min 8 ml. of trifiuorothloacetyl ethylene. fluoride. .do 150 420 150 500 240 min. 30flml. (11f trifluorothioacetyl ehlorotri- 150 440 150 480 180 min. 64 g of ehlorodifiuorothiofiuoroacetyl fluoride. ethylene. perfluoro- 150 420 470 240 min. 9.8 g. of perfiuorothiophaneg c u a-thione. trifiuoro 150 420 150 400 min. ditluorothioaeetyl fluoride.

ethylene. hexafiuoro- 440 370-450 4hrs. 130 g. hexafiuorothioaeetone, propylene. HgIIlIGXSflUOIOthiOZLCGtOHB active carbon prepared from wood, sawdust, peat, lignite and pulp-mill waste is preferred. Active carbon is ob- The examples set forth are illustrations of the invention described and are not to be construed as limiting the invention. Various modifications of the process equip ment will be apparent to those skilled in the art and are included in the scope of the present invention. The process described provides an economic and ready manufacture of fluorothiocarbonyl compounds from fluoroolefins and sulfur.

I claim:

1. A process for the preparation of fluorothiocarbonyl compounds which comprises contacting at a temperature of 250 C. to 750 C., a mixture of vaporized sulfur and a non-aromatic fluoroolefin having the general formula wherein R and R are radicals selected from the class consisting of fluorine, fluorocarbon radicals and divalent fluorocarbon radicals formed from the combination of R and R and R is a radical selected from the class consisting of hydrogen, fluorine, chlorine, and fluorocarbon radicals, with active carbon.

2. A process for the preparation of fluorothiocarbonyl compounds which comprises contacting at a temperature of 350 C. to 450 C., a mixture of vaporized sulfur and a fluoroolefin having the general formula References Cited in the file of this patent UNITED STATES PATENTS Bruce Jan. 26, 1960 Marquis Nov. 29, 1960 OTHER REFERENCES Brandt et 211.: J. Chem. Soc. (London), vol. of 1952, page 2201.

Lovelace: Aliphatic Fluorine Compounds, page 222 (1958). 

1. A PROCESS FOR THE PREPARATION OF FLUOROTHIOCARBONYL COMPOUNDS WHICH COMPRISES CONTACTING AT A TEMPERATURE OF 250*C. TO 750*C., A MIXTURE OF VAPORIZED SULFUR AND A NON-AROMATIC FLUOROOLEFIN HAVING THE GENERAL FORMULA 